package JavaSE.d4;

public class Test3 {
    public static void main(String[] args) {
        String s="aaaBBBB你好";

        String out=s.toUpperCase();//toUpperCase()将字符串转成大写
        System.out.println(out);

        out=s.toLowerCase();//toLowerCase()将字符串转成小写
        System.out.println(out);
    }
}
